ERBB2 and breast cancer: Moreover, the results of the Cancer Genome Atlas (TCGA) project, which analyzed tumor and germline DNA samples from 825 patients at the genomic, transcriptomic, and proteomic levels to establish clusters of tumors with molecular similarities, confirmed the existence of four intrinsic subtypes of breast cancer based solely on mRNA expression profiles: Luminal A, Luminal B, HER2-enriched, and Basal-like [84].